Groundwater & Ecosystems

Many aquatic ecosystems which are classified as surface water bodies are partially or wholly dependent on interactions with groundwater to sustain ecological structure and function. This includes springs, wetlands, pans or vleis, karst and cave systems, those rivers and estuaries with a strong baseflow component especially in the dry season.

Quite often, the interaction between groundwater and surface water is not adequately quantified. This may be because the interaction is complex and difficult to measure, or it may be simply because people haven’t considered that the interaction might be important and so don’t give it sufficient attention in their research or field measurement programmes. Another reason why the interaction is poorly understood is because groundwater and surface water hydrologists have generally worked separately in the past. Hydrological models have often been developed independently, with a resulting mismatch in scale and resolution (both temporal and spatial) between surface water and groundwater models, and often substantial inaccuracies in estimates of the groundwater contribution to surface water flow, or the surface water recharge to groundwater. Groundwater and surface water hydrologists tend to use different terminology, leading to confusion when trying to build integrated conceptual models.

Poor or inadequate quantification of the groundwater-surface water interaction means that management decisions (for example the abstraction of groundwater in the riparian zone of rivers) may be made without sufficient information on the potential impacts on aquatic ecosystems.

The issue of groundwater interactions with aquatic ecosystems is becoming the subject of increasing attention, as the body of research into determination of the water requirements of ecosystems grows, and as more emphasis is placed on integrated water resource management. Exciting new research is showing that groundwater fauna and flora are far more prevalent, diverse and complex than anyone has realised, and is helping to expose ecological processes which act at the interface between groundwater and surface water.

The purpose of this feature, on Groundwater and Ecosystems, is to provide references to useful web sites where interested people can find documents on current or recent projects, or can link up with others working in the field. We hope to build up a comprehensive list of references as interest in the topic grows worldwide.

General policy and management

This paper outlines, complexities of management of groundwater-dependent ecosystems, importance of groundwater dependant ecosystems (GDEs), how GDEs can be effected and information gaps in present understanding of GDEs.

Groundwater quality protection policy for New South Wales, Australia.

Groundwater Policy Framework for New South Wales, Australia.

A paper outlining a management approach based on the method of conservation of mass, applied to groundwater and aquatic ecosystem management in South Africa. Practical management considerations are outlined.

Insights into potential policy (state level in Australia) of groundwater allocation of GDE.

Hatton, Tom and Evans, Richard. (1998). Dependence of Ecosystems on Groundwater and its Significance to Australia. Land and Water Resources Research and Development Corporation, Occasional Paper No 12/98. pp. 77.

Specific case studies

A paper on using geo-chemical tracers to quantify groundwater discharge to the Indian river lagoon, Florida. Links are available to the case study.

A discussion paper on the potential of over extraction of water from the Murrumbidgee system. General issues required for an integrated groundwater and surface water management plan are covered.

A management paper towards integrated groundwater and surface water management. Examples from South Africa are provided.

This poster covers groundwater and surface water interactions in freshwater wetlands in Taylor Slough, Florida. The poster contains links to the problems and approach of the study and surface tracers used to determine groundwater interactions and the source and quality of groundwater discharge.

A summary final report on the development of best management practices for water and riparian resources along the Santa Cruz watershed, New Mexico. Discussion of negative impacts as a result of groundwater extraction.

Groundwater-surface water interactions in the Kissimmee River.

Development of minimum water level criteria for the Everglades Protection Area.

Guidelines for identification of karst and other subterranean water resources as wetlands of international importance. Resolution passed at COPVII of the Ramsar Convention.

Determination of the groundwater component of water requirements for aquatic ecosystems – a manual published by the South African Department of Water Affairs and Forestry.

Determination of the baseflow index (to identify and estimate the groundwater contribution to surface water flow in aquatic ecosystems – see Appendix 13 of the River Ecosystems manual.

Description of completed project on groundwater-surface water interactions in Australia.

A proposal outline, for research into groundwater and surface water exchange flux interactions in relation to water quality in the Florida Everglades. Particular focus on monitoring nutrient and mercury recycling. Several links to similar projects. http://sofia.usgs.gov/projects/index.php?project_url=wtr_flux

New research on groundwater fauna and the application to understanding of groundwater-surface water interactions – contact Prof Gert Steyn at the Rand Afrikaans University gjs@na.rau.ac.za , and Dr Bill Humphreys at the Museum of Western Australia bill.humphreys@museum.wa.gov.au

Hard copy references

Extensive hard copy references into wetland hydrology with several references to groundwater influences on wetland functioning.

A bibliography of over 200 hard copy related papers on groundwater dependent ecosystems.

CSIRO in Australia have a research programme on groundwater and ecosystem links - the Groundwater Resources and Ecosystems Interactions programme.

Related Events

IAH conference with a strong emphasis on groundwater interactions with the environment, to be held in Australia, May 2002.

Who’s doing what ?

This is a new section which will be added to all features, and which we would like to develop as time goes on. The aim is to provide a list of people or groups which are working in a specific field, to make it easier to establish contact with other researchers or colleagues who might be able to collaborate or provide information. If you would like to be added to this list, please email me hmackay@global.co.za, providing the website address of your group plus two to three sentences about who you are and what you do. If you don’t have a website, then please provide the name and email address of the relevant contact person.

Australia:

CSIRO Australia has a research programme on Groundwater Resources and Ecosystems Interactions

The Centre for Groundwater Studies in Adelaide, Australia has a research programme on Groundwater and the Environment.

Land and Water Australia funds research on, amongst other issues, groundwater-ecosystems interactions.

South Africa:

The Water Research Commission funds research on groundwater and ecosystems. http://www.wrc.org.za The web site lists current and recently completed projects. Contact Kevin Pietersen kevin@wrc.org.za

Parsons and Associates Specialist Groundwater Consultants – Roger Parsons was the leader of the team which developed the manual on determination of the groundwater component of water requirements for aquatic ecosystems rparsons@iafrica.com

Dave Le Maitre and Christine Colvin of Environmentek, CSIR, are currently completing a 3 year project for the Water Research Commission on groundwater dependency of terrestrial ecosystems.
The project focuses on South African ecosystems and proposes a protocol and tools available to assess groundwater use and dependency.
(We don't have a project specific site.) Email Christine Colvin ccolvin@csir.co.za

The Department of Water Affairs in South Africa has a Directorate: Geohydrology, whose staff are involved in determinations of the ecological Reserve (water quantity and quality requirements of ecosystems).

The research group at the University of the Western Cape is currently undertaking a project entitled: Hydrogeology of fractured aquifers and related ecosystems with dolerite ring and sill systems in the Eastern Cape. The aim of the research is to assess the vulnerability of ecosystems (plants and springs) to groundwater abstraction at various depth. Contact Dr Luc Chevallier luc@geobell.org.za